Structural Monitoring of Steel Member Bridge with Fatigue Life Prognosis Due to Dynamic Vehicular Loads

Details

• Creators:
  Wang, Yang ; Sherman, Ryan J. ; de Haaff, Zachary ; Wang, Zhengbo
• Corporate Creators:
  Georgia Institute of Technology
• Corporate Contributors:
  Georgia. Department of Transportation. Office of Performance-Based Management & Research ; United States. Department of Transportation. Federal Highway Administration
• Subject/TRT Terms:
  Data Analysis Fatigue (Mechanics) Long-term Monitoring Monitoring Nondestructive Tests Steel Bridges Structural Health Monitoring Wireless Sensor Networks
• Publication/ Report Number:
  FHWA-GA-25-2218
• Resource Type:
  Tech Report
• Geographical Coverage:
  United States ; Georgia
• Edition:
  Final Report: Nov 2022 – Nov 2025
• Corporate Publisher:
  Georgia. Department of Transportation. Office of Performance-Based Management & Research
• Abstract:
  A critical durability factor for steel bridges is the long-term fatigue performance, which depends on the structure’s fatigue details, stress range, and cycle counts. Modern bridges account for these factors and have an infinite service life; however, bridges designed using previous fatigue provisions may experience cracking. Given the importance of accurately predicting an existing bridge’s remaining fatigue life, an instrumentation system and a remaining fatigue life MATLAB application were developed in this project. The fatigue monitoring system utilized commercial data acquisition (DAQ) equipment capable of creating stress range histograms from measured nominal stress strain gage data. The remaining fatigue life was then calculated using the effective stress range and cycle count at each monitored location. In addition, a second DAQ system collected acceleration data for vibration modal analysis and finite element model updating. A framework was developed to use the updated model to estimate the effective stress range and cycle count at locations without strain gages. Both systems were deployed on two testbed steel bridges in Georgia: the Northside Bridge in Midtown Atlanta and the I-75SB Lake Allatoona Bridge. A series of controlled load tests were conducted to calibrate the finite element models and verify the performance of the instrumentation systems. Long-term fatigue monitoring was performed using the commercial DAQ system to estimate the remaining fatigue life of both bridges. The results show that for all details examined at the Northside Bridge, the constant amplitude fatigue threshold (CAFT) was not exceeded more than 0.01% of the time. On the I-75SB Lake Allatoona Bridge, the CAFT was not exceeded by more than 0.01% time at any location, except for one lateral connection plate. Extensive monitoring at additional lateral connection plate locations on the bridge is recommended. Overall, it was shown that the selected DAQ system and MATLAB application can provide reliable and efficient fatigue life assessments of steel bridges. The effective stress range and cycle count estimation framework developed using model updating showed some promise in estimating the effective stress range.
• Format:
  PDF
• Funding:
  PI# 0019328
• Collection(s):
  US Transportation Collection
• Main Document Checksum:
  urn:sha-512:be073e3606086e480dd9c0e142446162f76944b657f29d3bb55b7ca0788eb6d4534972c611a26c4848055c0d04947a6867ea27923b99f4dedc31cdfb05d89f26
• Download URL:
  https://rosap.ntl.bts.gov/view/dot/87523/dot_87523_DS1.pdf
• File Type:
  [PDF - 12.46 MB ]